Archive for the ‘Cycles’ Category


Dr David Whitehouse reviews the history of solar cycle predictions in a new paper by the Global Warming Policy Foundation which is published today. The paper, entitled The Next Solar Cycle, And Why It Matters For Climate, can be downloaded here.
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London, 6 April: A former BBC science correspondent says that there remains a real possibility that unusual solar behaviour could influence the Earth’s climate, bringing cooler temperatures for the next decade.


Encylopaedia Britannica on the Metonic cycle:

Metonic cycle, in chronology, a period of 19 years in which there are 235 lunations, or synodic months, after which the Moon’s phases recur on the same days of the solar year, or year of the seasons. The cycle was discovered by Meton (fl. 432 bc), an Athenian astronomer.

Calendar Wiki’s opening paragraphs on the Metonic cycle say:

The Metonic cycle or Enneadecaeteris in astronomy and calendar studies is a particular approximate common multiple of the year (specifically, the seasonal i.e. tropical year) and the synodic month. Nineteen tropical years differ from 235 synodic months by about 2 hours. The Metonic cycle’s error is one full day every 219 years, or 12.4 parts per million.

19 tropical years = 6939.602 days
235 synodic months = 6939.688 days

It is helpful to recognize that this is an approximation of reality.


Variation in solar activity during a recent sunspot cycle [credit: Wikipedia]

This seems worth another airing in the face of today’s insistent, but evidence-light, claims from climate obsessives that the world’s present and future weather is going to be largely determined by human activities.

If the energy from the sun varies by only 0.1 percent during the 11-year solar cycle, could such a small variation drive major changes in weather patterns on Earth? – asks Universe Today.

Yes, say researchers from the National Center for Atmospheric Research (NCAR) who used more than a century of weather observations and three powerful computer models in their study.

They found subtle connections between solar cycle, the stratosphere, and the tropical Pacific Ocean that work in sync to generate periodic weather patterns that affect much of the globe.

Scientists say this will help in predicting the intensity of certain climate phenomena, such as the Indian monsoon and tropical Pacific rainfall, years in advance.


Greenland ice sheet (east coast) [image credit: Hannes Grobe @ Wikipedia]

Of course the other question about the start of an ice age still remains.

New University of Melbourne research has revealed that ice ages over the last million years ended when the tilt angle of the Earth’s axis was approaching higher values, reports

During these times, longer and stronger summers melted the large Northern Hemisphere ice sheets, propelling the Earth’s climate into a warm ‘interglacial’ state, like the one we’ve experienced over the last 11,000 years.

The study by Ph.D. candidate, Petra Bajo, and colleagues also showed that summer energy levels at the time these ‘ice-age terminations’ were triggered controlled how long it took for the ice sheets to collapse, with higher energy levels producing fast collapse.

Researchers are still trying to understand how often these periods happen and how soon we can expect another one.


Wikipedia says:

Dansgaard–Oeschger events (often abbreviated D–O events) are rapid climate fluctuations that occurred 25 times during the last glacial period. Some scientists say that the events occur quasi-periodically with a recurrence time being a multiple of 1,470 years, but this is debated. —

The 25 occurrences of 1470 years are represented in this synodic chart posted in the comments of our 2018 blog post:
Possible origin of Dansgaard-Oeschger abrupt climate events.

Re. the ‘debate’, let’s take a line from this paper:
On the 1470-year pacing of Dansgaard-Oeschger warm events
Michael Schulz
First published: 01 May 2002
Citations: 99
‘a fundamental pacing period of ~1470 years seems to control the timing of the onset of the Dansgaard-Oeschger events.’

Another study: Timing of abrupt climate change: A precise clock
Stefan Rahmstorf
First published: 21 May 2003

An analysis of the GISP2 ice core record from Greenland reveals that abrupt climate events appear to be paced by a 1,470-year cycle with a period that is probably stable to within a few percent; with 95% confidence the period is maintained to better than 12% over at least 23 cycles. This highly precise clock points to an origin outside the Earth system; oscillatory modes within the Earth system can be expected to be far more irregular in period.

[bold added]

However, researchers often admit defeat when looking for a viable mechanism to explain its regularity, or just say there isn’t one to date.

Kepler’s trigon – the orientation of consecutive Jupiter-Saturn synodic periods, showing the repeating triangular shape (trigon).

Returning to the synodics chart, a relevant number doesn’t appear in it. The Jupiter-Saturn conjunction of 19.865~ years is an important period in the solar system, and it returns to almost the same position after every three occurrences, as Johannes Kepler noted with his ‘trigon’, centuries ago.

We can work out the rate of movement per conjunction in degrees:
360 – ((360 / S) * J-S) = 117.147 degrees
(360 / 117.147) * J-S = 61.046482y (‘JS-360’)
[Data: ]

Then, from the chart:
1470*25 / ‘JS-360’ = 602.00029
Check: (602*360) / 117.147 = 1849.983 (1850 J-S, see chart)
Since ‘JS-360’ is almost exactly a whole number (602), the Jupiter-Saturn conjunction should be in its original position at the end of the 25 D-O cycles.

Adding 602 to the orbits of each planet = multiples of 25:
223(N) + 602 = 825 (25*33) = 1850-1025(S-N)
[33 = 74-41]
1248(S) + 602 = 1850 (25*74)
3098(J) + 602 = 3700 (25*74*2)

Another way to get multiples of 25:
Add 2 to each orbit number (see chart), and subtract 2 from 602.

More on the 602 number:
602 = 14*43
14*61.046482y = 854.651y
43 J-S = 854.197y
These two results are only about half a year apart, and we find:
43*43 = 1849 J-S
Add 1 = 1850 J-S completing the 25 D-O cycle.

43*61.046482y = 2625 years (2624.9987)
1470:2625 = 14:25 ratio
1470*25 = 2625*14 (hence 602 of ‘JS-360’ = 14*43)

Obliquity note:
28 D-O = 41160 years, a fair match to the expected 41 kyr period.
One paper refers to a fit between D-O and obliquity.
Others support the notion of a link — possibly a topic for another post.
(28*25*1470 = 1,029,000 years)

Example of a 1470 year period from Arnholm’s solar simulator — click on image to enlarge:

Showing Neptune, Jupiter, Saturn and Earth.
* * *
Another one — Jupiter, Neptune, Saturn

Image credit:

The aim here is to show how the synodic periods and orbits of these three planets align with the so-called Grand Synod, a period of about 4628 years which has 27 Uranus-Neptune conjunctions and almost 233 Jupiter-Saturn conjunctions. Its half-period is sometimes referred to as the Hallstatt cycle (2314 years +/- a variable margin).

1. U-N ‘long period’
1420 Uranus-Neptune conjunctions = 1477 Neptune orbits
(for calculations, see Footnote)
1477 – 1420 = 57
Uranus-Neptune 360 degrees return is 1420/57 U-N = 24.91228 U-N long period = 4270.119 years

2. GS : U-N ratio
Grand Synod = 27 U-N = 4627.967 years (= ~233 Jupiter-Saturn conjunctions)
27 / 24.91228 = 1.0838028
1.0838028 * 12 = 13.005633
Therefore the ratio of 4627.967:4270.119 is almost exactly 13:12 (> 99.956% true)

3. Orbital data
Turning to the orbit periods nearest to the Grand Synod:
28 Neptune = 4614.157y
55 Uranus = 4620.927y
(Data: )

4. Factor of 12
These periods fall slightly short of the 27 U-N Grand Synod (~4628 years).
However, multiplying by 12 and adding one orbit to each, gives:
28*12,+1 (337) Neptune = 55534.67y
55*12,+1 (661) Uranus = 55535.14y
27*12 (661 – 337) U-N = 55535.61y

Now the numbers match to within a year +/- 55535 years.
Also, the period is 12 Grand Synods (12*4628 = 55536y), or 13 U-N ‘long’ periods.

5. Pluto data
Pluto’s orbit period is 247.92065 years.
55535 / 247.92065y = 224.003
So 224 Pluto orbits also equate to 12 Grand Synods.

Therefore, a U-N-P synodic chart can be created for that period of time.

6. Neptune:Pluto orbits
Neptune has one more orbit in the period than an exact 3:2 ratio with Pluto – a planetary resonance.
224 P = 112*2
337 N = 112*3, +1
113 N-P = 112, +1

7. Phi factor
Uranus and Neptune both have one more orbit than this ratio:
660:336 = (55*12):(21*16)
55/21 = Phi²
12/16 = 3/4
Therefore the U:N ratio is almost (3/4 of Phi²):1

The U-N-P chart should repeat every 12 Grand synods i.e. every 55,535 years or so.
– – –
360 / Neptune orbit (164.79132) = 2.184581
2.184581 * U-N conjunction (171.40619) = 374.4507
374.4507 – 360 = 14.4507

Obtain nearest multiple of 360 degrees:
1420 * 14.4507 = 20519.9994
20520 / 360 = 57
1420 + 57 = 1477
1420 U-N = 1477 Neptune orbits
1420 + 1477 = 2897 Uranus orbits

Solar system [credit: BBC]

This new paper from our good friend Nicola Scafetta takes another look at the Sun’s cyclic behaviour and possible planetary influences on it, referencing various researchers whose work has appeared at the talkshop, along the way.
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Gravitational planetary lensing of slow-moving matter streaming towards the Sun was suggested to explain puzzling solar-flare occurrences and other unexplained solar-emission phenomena (Bertolucci et al. in Phys. Dark Universe 17, 13, 2017). If it is actually so, the effect of gravitational lensing of this stream by heavy planets (Jupiter, Saturn, Uranus and Neptune) could be manifested in solar activity changes on longer time scales too where solar records present specific oscillations known in the literature as the cycles of Bray–Hallstatt (2100–2500 yr), Eddy (800–1200 yr), Suess–de Vries (200–250 yr), Jose (155–185 yr), Gleissberg (80–100 year), the 55–65 yr spectral cluster and others. It is herein hypothesized that these oscillations emerge from specific periodic planetary orbital configurations that generate particular waves in the force-fields of the heliosphere which could be able to synchronize solar activity.


ISSN 1063-7737, Astronomy Letters, 2019, Vol. 45, No. 11, pp. 778–790.c Pleiades Publishing, Inc., 2019. Nicola Scafetta1*,FrancoMilani2, and Antonio Bianchini3, 41Department of Earth Sciences, Environment and Georesources, University of Naples Federico II,Complesso Universitario di Monte S. Angelo, via Cinthia, 21, 80126 Naples, Italy 2 Astronomical Association Euganea, via N. Tommaseo, 70, 35137 Padova, Italy3INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy 4 Department of Physics and Astronomy, Universit `a degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy Received May 18, 2019; revised October 2, 2019; accepted October 23, 2019


Still waiting

More so than the climate alarm movement thought, anyway. Hence all the failed predictions of disappearing summer sea ice in the Arctic, and erroneous claims of ‘rapid melting’ that no longer hold water 😎
Observations show a ‘sideways trend’ in Arctic sea ice volume since around 2010, which perhaps not by chance follows a significant downturn in solar cycle intensity.
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In recent years the Arctic sea ice has shown great resiliency and is currently at higher levels for this time of year when compared to all but two years going back to 2005, says meteorologist Paul Dorian of Perspecta Inc. (via The GWPF).


Sea ice covers about 7% of the Earth’s surface and about 12% of the world’s oceans and forms mainly in the Earth’s polar regions.


Earth’s tilt moves back and forth between about 22 and 24.5 degrees

If there is a mean ratio of 5:8 it would be linked to the known variation of Earth’s tilt, which in turn causes variation in the precession and obliquity periods.

Encyclopedia Britannica’s definition says:
Precession of the equinoxes, motion of the equinoxes along the ecliptic (the plane of Earth’s orbit) caused by the cyclic precession of Earth’s axis of rotation…The projection onto the sky of Earth’s axis of rotation results in two notable points at opposite directions: the north and south celestial poles. Because of precession, these points trace out circles on the sky.

(Axial precession is another term for ‘precession of the equinoxes’).

Our 2016 unified precession post started with this quote from Wikipedia (bolds added):
Because of apsidal precession the Earth’s argument of periapsis slowly increases; it takes about 112000 years for the ellipse to revolve once relative to the fixed stars. The Earth’s polar axis, and hence the solstices and equinoxes, precess with a period of about 26000 years in relation to the fixed stars. These two forms of ‘precession’ combine so that it takes about 21000 years for the ellipse to revolve once relative to the vernal equinox, that is, for the perihelion to return to the same date (given a calendar that tracks the seasons perfectly).

Three linked precessions

In units of 1,000 years:
21 * (16/3) = 112
112 * (3/13) = 25.846~ (near 26)
25.846~ * (13/16) = 21
That was the number theory of the ‘unified precession’ post, i.e. a 3:13:8*2 ratio.

Where might the obliquity period, known to be somewhere near 41,000 years, fit into that?

Referring to the chart (above, right) and converting decimals to whole numbers:
AY – SY = 328 = 109*3, +1
SY – TY = 1417 = 109*13
AY – TY = 1745 (328 + 1417) = 109*16, +1
[327:1417:1744 = 3:13:16]

So that supports the number theory.

Starting out, I just updated the chart to include an entirely theoretical obliquity period of 8/5 times axial precession, linking it to the other known cycles as suggested by my 2016 comment to the unified precession post, here.

That post was a follow-up to: Why Phi? – some Moon-Earth interactions, which showed how:
The period of 6441 tropical years (6440.75 sidereal years) is one quarter of the Earth’s ‘precession of the equinox’.
Multiplying by 4: 25764 tropical years = 25763 sidereal years.
The difference of 1 is due to precession.

[NB Wikipedia quotes 25772 years (‘disputed – discuss’) for this precession cycle, but as it’s not a fixed number the question is: what is the mean period? Earth is currently around the mid-point of the tilt variation, moving towards minimum tilt i.e a shorter precession period. Astronoo says 25765 years.]

But then I came across two things: a paper by EPJ van den Heuvel, cited in Wikipedia, and another entry in Wikipedia (see below), that together suggested viable alternative numbers but with the same 5:8 ratio.

On the Precession as a Cause of Pleistocene Variations of the Atlantic Ocean Water Temperatures
— E. P. J. van den Heuvel (1965)

From the summary:
‘The Fourier spectrum (Fig. 8) shows two significant main periods, P1 = 40000 years and P2 = 12825 years*. The first period agrees well with the period of the oscillations of the obliquity of the ecliptic. The second period corresponds very well with the half precession period.’
[*But the specific periods found were: 42857, 39474 and 12825 years]

From Wikipedia – Axial tilt – long term (Wikipedia):
‘For the past 5 million years, Earth’s obliquity has varied between 22° 2′ 33″ and 24° 30′ 16″, with a mean period of 41,040 years. This cycle is a combination of precession and the largest term in the motion of the ecliptic.’

41040:12825 = 16:5 exactly. Since 12825 is the half precession period, the full period ratio is 8:5 as in the chart, but with slightly different numbers.

If this is correct, the 25764y period in the chart would need adjusting by a factor of 225/226:
25764 * (225/226) = 25650 = 2 * 12825

The Wikipedia obliquity period of 41040 years is divisible by 19, so is an exact number of Metonic cycles (2160), as is the revised axial precession of 25650 years (1350). So the alternative period equals a reduction of 6 Metonic cycles of axial precession. The idea of a role for the Moon in Earth’s obliquity has been put forward before.

Of course 225/226 represents less than half a percent of correction, so could be argued to be negligible.
– – –
Now something else has turned up, written around the same time as two Talkshop posts already referred to:
The Secret of the Long Count, by John Martineau

In the ‘Long Count’ section of the article the writer also puts forward an argument for a (mean) 5:8 ratio of obliquity and axial (equinoctial) precession, using some historical context (see below).

So at least one other person has been thinking along the same lines. Note that 2,3,5,8 and 13 are Fibonacci numbers.

– – –
The Secret of the Long Count

In the summer of 2012 I visited Carnac, accompanied by Geoff Stray. Howard Crowhurst runs an annual midsummer conference there and we had been invited to speak at the 2012-themed event. Halfway through his presentation, Crowhurst was describing his hunches surrounding megalithic awareness of the 41,000-year cycle, when he casually mentioned a startling fact:

The 41,000-year cycle very precisely consisted of eight Mayan Suns.

I did a double take. Eight suns, but five made precession! Startled, I cornered Geoff Stray. He had already come across the eight Suns figure for the obliquity cycle, but not realised the significance of 5:8, while Howard Crowhurst had been unaware of the fact that five Suns gave a value for Precession. We had cracked it.

One Mayan Sun is 5,125 years.

Five Suns give the Precessional Cycle

5 x 5125 = 25,625 years (current value 25,700 years, 75 years out)

Eight Suns give the Earth’s Obliquity Cycle.

8 x 5125 = 41,000 years (current value 41,040 years, 40 years out)

Five and eight! The two long cycles that most affect the Earth relate as 5:8 and are both encoded by the Long Count. The Maya must have known. No wonder they drew so many pictures of jawbones. Five and eight! The same two numbers displayed by human teeth are the same two numbers as those used by the plants all around us, and these are the same two numbers that connect us with our closest neighbour Venus, and the same two numbers that relate the two long cycles that affect Earth-bound astronomy.

[emphasis by the author]

From: The Secret of the Long Count, by John Martineau

A Coronal Mass Ejection with the surrounding cloud visible (1999) [image credit: NASA/ESA]

Even non-catastrophic solar storms can be troublesome, such as one in 1967 which nearly triggered nuclear war, according to evidence from retired U.S. Air Force personnel.
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A ‘great’ space weather super-storm large enough to cause significant disruption to our electronic and networked systems occurred on average once in every 25 years, according to a new joint study by the University of Warwick and the British Antarctic Survey.

By analysing magnetic field records at opposite ends of the Earth (UK and Australia), scientists have been able to detect super-storms going back over the last 150 years, reports

This result was made possible by a new way of analysing historical data, pioneered by the University of Warwick, from the last 14 solar cycles, way before the space age began in 1957, instead of the last five solar cycles currently used.


Visualization of the Radcliffe Wave. The wave is marked by red dots. The Sun is represented by a yellow dot to show our proximity to this huge structure. Courtesy of Alyssa Goodman/Harvard University

Scientists have previously reported evidence for a 26-million-year cycle of extinction on Earth, but the idea has remained controversial and unexplained. Now the discovery of the Radcliffe Wave may offer an explanation, but has anyone so far said so?

The team also found the wave interacts with the Sun. It crossed our path about 13 million years ago and will again in another 13 million years. What happened during this encounter is also unknown.

“There was no obvious mass extinction event 13 million years ago, so although we were crossing a sort of minefield back then, it did not leave an obvious mark,” Alves said. “Still, with the advent of more sensitive mass spectrometers, it is likely we will find some sort of mark left on the planet.”

13+13 = 26 (million). Can such a mark be found?
– – –
From the article, ‘Something Appears to Have Collided with the Milky Way and Created a Huge Wave in the Galactic Plane’:


Pacific Decadal Oscillation (PDO) [credit: NASA-JPL]

AMO & PDO – RIP. That’s the claim here anyway. Might be news to NASA and others.

Recently, meteorologists report that the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) do not appear to exist, says Tech Explorist.

The discovery could have implications for both the validity of previous studies attributing past trends to these hypothetical natural oscillations and for the prospects of decade-scale climate predictability.

The discovery is based on observational data and climate model simulations, that shows there was no reliable proof for decadal or longer-term internal oscillatory signals that could be separated from climatic noise— arbitrary year to year variation.

The apparent main swaying is the well-known El Niño/Southern Oscillation (ENSO).


Mount Etna, Sicily

The article says: ‘Every 6.4 years, the axes line up and the wobble fades for a short time.’ This looks a lot like 5.4 Chandler wobbles (CW), so you would have 6.4 years minus 5.4 CW = 1 cycle, i.e. 32:27 ratio = 5 (32-27) cycles.
Much more analysis of this time period and related matters in this 2013 Talkshop post:
Ian Wilson: Solar System Timings Evolved Lunar Orbital Elements Linked to Earth’s Chandler Wobble

New research suggests forces pulling on Earth’s surface as the planet spins may trigger earthquakes and eruptions at volcanoes, reports

Seismic activity and bursts of magma near Italy’s Mount Etna increased when Earth’s rotational axis was furthest from its geographic axis, according to a new study comparing changes in Earth’s rotation to activity at the well-known Italian volcano.


Variation in solar activity during a recent sunspot cycle [credit: Wikipedia]

A new study has found winters in northern China have been warming since 4,000BC – regardless of human activity – but the mainland scientists behind the research warn there is no room for complacency or inaction on climate change, with the prospect of a sudden global cooling also posing a danger.

The study found that winds from Arctic Siberia have been growing weaker, the conifer tree line has been retreating north, and there has been a steady rise in biodiversity in a general warming trend that continues today. It appears to have little to do with the increase in greenhouse gases which began with the industrial revolution, according to the researchers.


Jupiter-Saturn-Earth orbits chart

This was just about to go live when a new idea involving the Sun cropped up, now added to the original. The source data is from NASA JPL as usual.

From our 2015 de Vries post we saw that the 2503 year period, which the numbers were based on, consisted of 85 Saturn and 211 Jupiter orbits [see chart on the right].

Taking Saturn’s orbit period, and using JPL’s planetary data we find:
10755.7 days * 85 = 914234.5 days

The lunar year is 13 lunar orbits of Earth:
27.321582 days * 13 = 355.18056 days

914234.5 / 355.18056 = 2573.9992 (2574) = 13 * 198 lunar years

Number of beats of Saturn and the lunar year = 2574 – 85 = 2489 in 2503 years.
2503 – 2489 = 14
Number of Jose cycles in 2503 years = 14 (= 126 Jupiter-Saturn conjunctions, i.e. 9 J-S * 14).

Therefore the difference per Jose cycle between ‘Saturn-lunar year’ beats and Earth years is exactly one.


Ice core sample [image credit: Discovering Antarctica]

Of course they are pushing the usual doom and gloom messages based on dubious greenhouse gas theories, but a glimmer of light perhaps is that they accept the Earth has warmed and cooled in the past due to unknown factors. They in effect admit the obvious, namely that attribution of climate change to humans in some, or any, degree cannot be quantified at present. But the bluffing goes on.

As the pace of global warming outstrips our ability to adapt to it [Talkshop comment – allegedly], scientists are delving deep into the distant past, hoping that eons-old Antarctic ice, sediments and trees chart a path to navigate our climate future, says

“What interests us is to understand how the climate works,” says Didier Roche of France’s National Centre for Scientific Research (CNRS).

At the Laboratory for Climate and Environment Sciences (LSCE), just outside Paris, the aim is to establish a comprehensive record of climate change dating back hundreds of thousands of years, to chart the repeated warming and cooling cycles the Earth has gone through and to try to understand what drives them.


The full GWPF paper is here. Needless to say, it offers little comfort to ‘man-made warming’ climate dogmatists. The author concludes that what is happening to the oceans today is not unusual, in historical terms.

Executive summary

• The study of ocean heat content (OHC) is a subject struggling with inadequate data, but exposed in a public forum.

• Only since the introduction of data from the Argo array have there been convincing estimates of errors. The inhomogeneity of different data sets is a major problem.

• There is no real understanding of the difference between random and systematic errors in OHC data.

• Changes in OHC are at the limits of our ability to measure, and made with much uncertainty and many unknowns.


‘Long-term’ here means really long-term. The 21k year precession period quoted looks like that of the perihelion.

In the past million years, the high-altitude winds of the southern westerly wind belt, which spans nearly half the globe, didn’t behave as uniformly over the Southern Pacific as previously assumed.

Instead, they varied cyclically over periods of ca. 21,000 years, reports ScienceDaily.

A new study has now confirmed close ties between the climate of the mid and high latitudes and that of the tropics in the South Pacific, which has consequences for the carbon budget of the Pacific Southern Ocean and the stability of the West Antarctic Ice Sheet.


The question then is: how much life will it come to, compared to recent cycles?
Cycle 25 observations in SDO HMI imagery (to October 31st, 2019)

Nov. 1, 2019: Breaking a string of 28 spotless days, a new sunspot (AR2750) is emerging in the sun’s southern hemisphere–and it’s a member of the next solar cycle. A picture of the sunspot is inset in this magnetic map of the sun’s surface from NASA’s Solar Dynamics Observatory:


How do we know AR2750 belongs to the next solar cycle? Its magnetic polarity tells us so. Southern sunspots from old Solar Cycle 24 have a -/+ polarity. This sunspot is the opposite: +/-. According to Hale’s Law, sunspots switch polarities from one solar cycle to the next. AR2750 is therefore a member of Solar Cycle 25.

Shortlived sunspots belonging to Solar Cycle 25 have already been reported on Dec. 20, 2016; April 8, 2018; Nov. 17, 2018; May 28, 2019; July 1, 2019; and July 8, 2019. The one on July 8, 2019, was significant because it lasted long…

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